1. Field of the Invention
The present invention relates to a method and a device of correcting received levels in a mobile communication terminal, and more particularly, to a method and a device of correcting received levels in a mobile communication terminal capable of improving a reception efficiency and a communication quality of the mobile communication terminal by correcting received levels for each channel received at the mobile communication terminal.
2. Background of the Related Art
Generally, a mobile communication terminal comprises a radio frequency module. The radio frequency module performs a function of receiving radio signal from a base station and also measures an intensity of the radio signal received from the base station.
In this case, the intensity of the radio signal measured by the radio frequency module can be shown as a numerical value of a received signal strength indicator (RSSI) which is a received level. In general, the ‘received signal strength indicator’ is a mean strength index of received signal intensities, which can be obtained by measuring intensities of all radio signals received at a mobile communication terminal.
A ‘correction’ of the RSSI is obtained by measuring received levels of a reference channel and other channels, then storing difference values between the received levels measured and correcting received levels in actual network using the stored values, where a cell power of a broadcasting channel (BCH) transmitted from the base station is regulated to 62 dBm.
With regard to the correction of the RSSI, it is not easy to measure and store RSSI values for all channels received at the mobile communication terminal. Accordingly, a method is currently used that only one channel per a predetermined number of channels, for example ten (10) channels, is representatively selected as main channel(MC). In this case, only the selected main channel's RSSI value is measured and RSSI values of the other 9 channels are not measured. The measured RSSI value of the main channel can be applied as that of each channel of which RSSI value is not measured.
However, according to the above method, even if the RSSI value of the main channel is measured to be abnormally large(that is, the signal is very highly bounced) by a certain cause, the abnormal RSSI value is, as it is, applied to each channel of which RSSI values is not measured.
In order to decrease a risk that the above problem occurs, a method that measures RSSI values of two main channels and then applies a mean value of the measured RSSI values as that of channels between the two main channels can be used.
For example, there is a method that a mean value, which is obtained by adding a RSSI value measured in the channel ‘0’ to a RSSI value measured in the channel ‘9’ and then dividing the sum by two (2), is applied as RSSI values of channels whose absolute radio frequency channel numbers (ARFCNs) are ‘0’ to ‘9.
However, even though the mean of the RSSI values of the two main channels is applied, there can still be occurred a bad result when compared to applying actual RSSI value.
Accordingly, there is needed a technique capable of applying a value close to a actual RSSI value to each channel of which RSSI value is not measured while measuring only a RSSI value of a main channel.